A novel factor for primary arteriovenous fistula failure: hyperinsulinism.

INTRODUCTION: Dysfunction of vascular access is an important reason of morbidity for dialysis patients and it is a major factor affecting the economical burden of hemodialysis. The preferred type of vascular access is creation of an arteriovenous fistula (AVF). However, the problem of fistula maturation rate is still a challenge. Herein, we tried to search the role of hyperinsulinism and insulin resistance as a new predictor of primary AVF failure (pAVFF) that may be a cause of intimal damage. METHODS: We included 119 patients (73 male and 46 female) with a diagnosis of end-stage renal disease (ESRD) who had undergone an AVF operation by a vascular surgeon. The AVF was examined for presence of thrill on the first postoperative day. A successful cannulation with two fistula needles with a blood flow of 250 mL/min for at least one complete dialysis session, after 4 weeks of AVF surgery was defined as functioning access. Insulin resistance in our patients was determined by the standard homeostasis model assessment (homa-IR). A logistic-regression analysis was performed to investigate the independent factors related with pAVFF. FINDINGS: Detection of pAVFF occurred in 27 (22.7%) patients. The presence of thrill, amount of daily proteinuria, insulin levels, homa-IR, and serum albumin levels were found to be significantly different between patients with fistula failure and those without pAVFF. The logistic-regression analysis of preoperative factors revealed the following OR (odds ratio) and 95% CI values: homa-IR 1.205 (1.063-1.366) (p = 0.004), serum albumin 0.398 (0.178-0.892) (p = 0.025), and the amount of daily proteinuria 1.307 (1.012-1.688) (p = 0.041). Even after addition of the presence of postoperative thrill on AVF, which was a postoperative strong clinical factor to the analysis, mean homa-IR and mean serum albumin continued to be independent predictors of pAVFF. DISCUSSION: Insulin resistance or hyperinsulinism may be a significant cause of pAVFF, which emphasizes the role of endothelium in fistula dysfunction.

Surgical Excition of Spinal Intradural Meningiomas through a Single-Sided Minimally Invasive Approach: Key-Hole Laminotomy.

STUDY DESIGN: Eight patients who underwent surgery through a single-sided keyhole laminotomy due to intradural extramedullary (IDEM) meningiomas were retrospectively investigated. PURPOSE: To present the surgical outcomes of single-sided keyhole laminotomies aimed to excise large ventral IDEM spinal cord menengiomas. OVERVIEW OF LITERATURE: Less invasive procedures, such as laminotomies and osteoplastic laminotomies, have been previously described in the literature, but an approach that interferes with spinal stability to an even lesser extent would be more desirable. METHODS: Tumors were removed through a slit-like space between the dura and spinal cord without retraction of the spinal cord. The neurological conditions of patients were evaluated pre- and postoperatively with the Nurick grading system. Pathologic subtypes, preoperative symptom duration, tumor location on the sagittal and axial planes, and the percentage of tumor occupying the intradural space were investigated. On follow-up, magnetic resonance imaging was conducted to evaluate whether the tumor had recurred. RESULTS: All tumors were localized either ventrally or ventrolaterally. Of the spinal menengiomas, four were cervical and four were thoracic. All lesions were completely excised, and the neurological condition improved in six patients. The remaining two patients already had preoperative Nurick grades of 0, and this score was maintained postoperatively. Neither kyphotic changes nor instability developed in any patient during the follow-up period. CONCLUSIONS: Total resection of anterior and anterolateral IDEM menengiomas, without introducing new neurological deficits, can be performed by an isolated posterior approach through a single-sided keyhole laminotomy. However, this approach should be applied cautiously and with a thorough understanding of its limitations.

The effects of thyroid dysfunctions on insulin resistance in patients with hepatosteatosis.

BACKGROUND: Hepatosteatosis can develop due to insulin resistance. The effect of thyroid function status on insulin sensitivity and resistance is of great interest but the data is still conflicting. OBJECTIVES: The aim of this study was to evaluate the effects of thyroid dysfunctions on insulin resistance in patients with hepatosteatosis. MATERIAL AND METHODS: A total of 407 patients with hepatosteatosis were divided into three groups: 102 subjects with hypothyroidism, 103 with hyperthyroidism and 202 with normal thyroid function (control group). We measured serum thyroid stimulating hormone (TSH), free T4 (FT4) and free T3 (FT3) concentrations, blood glucose and insulin levels, serum lipid levels, hepatic transaminases and the homeostasis model assessment of insulin resistance (HOMA IR). RESULTS: Neither hypothyroidism patients nor hyperthyroidism patients showed significant differences in HOMA IR, glucose and insulin levels (p>0.05 for each). The frequency of insulin resistance was similar in all groups (p>0.05). CONCLUSIONS: Based on our findings, hypothyroidism and hyperthyroidism are not correlated to insulin resistance in patients with hepatosteatosis. Different causes which are associated with insulin resistance should be investigated in patients with thyroid dysfunction and hepatosteatosis.

Value of early unilateral decompressive craniectomy in patients with severe traumatic brain injury.

BACKGROUND: The aim of our study was to evaluate the results and effectiveness of early decompressive craniectomy in the treatment of severe traumatic brain injury. METHODS: We conducted a prospective study to investigate the clinical and radiological results of early unilateral decompressive craniectomy in 33 patients with severe traumatic brain injury. The mean area of the craniectomy, potential expansion volume of the decompressed brain, and distance between the lower border of the craniectomy and the temporal cranial base were calculated from computed tomography scans. Clinical results were analyzed with modified Rankin Scale (mRS). RESULTS: Time to surgery after trauma was 3.1+/-1.9 hours. There was a direct proportionality correlation between the area of the craniectomy and the calculated volume (p<0.0001). There was also a significant correlation between the state of the mesencephalic cisterns after craniectomy and the distance of the craniectomy to the base of the cranium (p<0.01). Assessment of overall one-year clinical outcome demonstrated favorable outcome (mRS 0-3) in 48.5% of patients. CONCLUSION: The high overall morbidity and mortality rates demonstrated in our group despite the performance of early decompressive procedures reflect the severity of the underlying injuries.

Brain abscess: analysis of results in a series of 51 patients with a combined surgical and medical approach during an 11-year period.

OBJECT: In this study the authors' goal was to present the clinical and imaging results of the combined surgical and medical treatment of intracranial abscesses. METHODS: The authors retrospectively analyzed the data in 51 patients with intracranial abscesses who underwent surgery between January 1997 and November 2007. Patients were treated with aspiration through a single bur hole, total resection with open craniotomy, or image-guided stereotactic aspiration. Computed tomography or magnetic resonance imaging was performed approximately 24 hours after surgery to evaluate the size of the abscess and almost weekly during follow-up until the abscess and/or cerebral edema was reduced. Clinical results were analyzed using modified Rankin Scale (mRS) scores. RESULTS: There were 36 male and 15 female patients, and their ages ranged from 14 months to 58 years (mean 29 years). Adjacent localized cranial infection was the most common predisposing factor in 31 patients (61%). Thirty-two patients were treated by repeated aspiration via a single bur hole. Streptococcus and Staphylococcus species were isolated most frequently. No statistically significant difference between causative organisms and clinical outcome was identified (p > 0.05). Assessment of overall 1-year clinical outcomes was favorable (mRS Scores 0-2) in 76.5% of patients (39 of 51 patients). The initial neurological condition was strongly correlated with the clinical outcome (p < 0.001). CONCLUSIONS: A combination of surgical aspiration or removal of all abscesses > 2.5 cm in diameter, a 6-week or longer course of intravenous antibiotics, and weekly neuroimaging should yield cure rates of > 90% in patients with intracranial abscesses.

A long-term follow-up study of anterior tibial allografting and instrumentation in the management of thoracolumbar tuberculous spondylitis.

OBJECT: The purpose of this study was to determine the efficacy of anterior instrumentation following radical debridement and tibial allografting and its long-term progression in patients with multilevel spinal tuberculosis. METHODS: This prospective observational study was undertaken to analyze 22 patients with multilevel spinal tuberculosis (Pott disease) who underwent anterior radical debridement, decompression, and fusion using anterior spinal instrumentation and tibial allograft replacement between 1999 and 2001. Clinical outcomes were assessed using the American Spinal Injury Association (ASIA) Impairment Scale and a visual analog scale (VAS). Preoperative and postoperative plain radiographs were obtained, and the focal kyphotic angle of the surgically treated spinal segments and the overall sagittal and coronal contours of the thoracic and lumbar spine were evaluated in all patients. RESULTS: The mean follow-up time was 84 months (range 36-96 months). All patients demonstrated clinical healing of the tuberculosis infection. All patients showed evidence of successful bone fusion. The mean late postoperative kyphosis correction was 74% (range 63-91%). On average, 2 degrees (range 0-5 degrees ) of loss of correction was noted in the local kyphotic angle postoperatively in late follow-up findings. Evaluation of the surgical effect on sagittal global contours showed a significant correction rate in thoracic, thoracolumbar, and lumbar regions. The mean late postoperative coronal plane alignment correction was 99%. The ASIA Impairment Scale scores demonstrated significant improvement in late follow-up results in our series. Surgical decompression also resulted in a dramatic reduction of overall pain in all patients (late postoperative VAS score 1.61 +/- 0.81). CONCLUSIONS: Anterior tibial allografting and instrumentation provide correction of the curvature, prevention of further deformation, improvement of sagittal and coronal balance, and restoration of neurological function in patients with spinal tuberculosis.

Transsellar transsphenoidal rhino-oral encephalocele.

Transsphenoidal encephaloceles are rare and the transsellar variety is the least common. We present a 1-year-old male patient with transsellar transsphenoidal encephalocele which herniated into the oral cavity through the congenital split palate. The patient was operated on using a combined transcranial and transpalatal approach without mortality or permanent morbidity. Clinical findings, imaging reviews, surgical repair techniques and postoperative morbidity are discussed with the relevant literature. We conclude that repair of a transsphenoidal encephalocele should be coordinated between a team of neurosurgeons and otorhinolaryngologists. Our surgical outcome supports a transcranial approach for the treatment of these difficult lesions, with transpalatal dissection and exposure.

Spinal cord compression caused by a brown tumor at the cervicothoracic junction.

BACKGROUND CONTEXT: Brown tumors are classic benign skeletal manifestations of hyperparathyroidism, but the spine involvement is very rare. Spinal reconstruction in these patients is controversial because of the severe osteoporosis and impaired bone healing. Of the reported 12 cases of spinal brown tumors in the literature, only in 5 were reconstructions with bone graft used. PURPOSE: To describe our management in a patient with brown tumor and also to review the previous published cases. STUDY DESIGN: Case report. METHODS: A case of a brown tumor in the T1 vertebra of a 72-year-old male patient is described. He had a previous diagnosis of secondary hyperthyroidism caused by renal failure. First, posterior transpedicular open biopsy was performed for the diagnosis and also for the decompression of the root causing brachialgia. After the diagnosis of a brown tumor, the patient was reoperated through anterior approach for total tumor removal and reconstruction of the spine. An autolog 3-cortical iliac crest strut graft was used for fusion, and medical treatment of hyperparathyroidism was given immediately after the operation. Decompression of spinal canal and fusion of bone graft was shown by a computed tomography scan 1 year after the operation. RESULTS: Complete resolution of the complaints of the patient and fusion of the graft were achieved. CONCLUSION: The determination of a spinal tumor in a patient with renal failure and hyperparathyroidism should bring to mind the probability of a brown tumor. Although it is of a benign nature, it can cause severe neurologic deficit because of spinal compression. The recommended treatment modality is surgical resection of the tumor, spinal reconstruction, and aggressive treatment of hyperparathyroidism both with parathyroidectomy and medically.

Efficacy of unilateral laminectomy for bilateral decompression in lumbar spinal stenosis.

OBJECTIVE: We have conducted a prospective study to evaluate the results and effectiveness of bilateral decompression via a unilateral laminectomy in 50 patients with 98 levels of degenerative lumbar spinal stenosis without instability. METHODS: Clinical outcomes were assessed using the Visual Analog Scale, Oswestry Disability Index, Short Form-36, and subjective Satisfaction Measurement. RESULTS: Adequate decompression was achieved in all patients. The mean follow-up time was 22.8 months (range 19 - 47 months). Surgical decompression resulted in a dramatic reduction of overall pain in all patients (late postoperative VAS score was 2.16 +/- 0.81). The ODI scores decreased significantly in early and late follow-up evaluations and the SF-36 scores demonstrated significant improvement in late follow-up results in our series. Patient satisfaction rate was 94%, and its improvement rate was 96%. CONCLUSION: For degenerative lumbar spinal stenosis with or without mild degenerative spondylolisthesis, the unilateral approach allowed sufficient and safe decompression of the neural structures and adequate preservation of vertebral stability, resulted in a highly significant reduction of symptoms and disability, and improved health-related quality of life.

Midterm outcome after unilateral approach for bilateral decompression of lumbar spinal stenosis: 5-year prospective study.

The aim of our study is to evaluate the results and effectiveness of bilateral decompression via a unilateral approach in the treatment of degenerative lumbar spinal stenosis. We have conducted a prospective study to compare the midterm outcome of unilateral laminotomy with unilateral laminectomy. One hundred patients with 269 levels of lumbar stenosis without instability were randomized to two treatment groups: unilateral laminectomy (Group 1), and laminotomy (Group 2). Clinical outcomes were assessed with the Oswestry Disability Index (ODI) and Short Form-36 Health Survey (SF-36). Spinal canal size was measured pre- and postoperatively. The spinal canal was increased to 4-6.1-fold (mean 5.1 +/- SD 0.8-fold) the preoperative size in Group 1, and 3.3-5.9-fold (mean 4.7 +/- SD 1.1-fold) the preoperative size in Group 2. The mean follow-up time was 5.4 years (range 4-7 years). The ODI scores decreased significantly in both early and late follow-up evaluations and the SF-36 scores demonstrated significant improvement in late follow-up results in our series. Analysis of clinical outcome showed no statistical differences between two groups. For degenerative lumbar spinal stenosis unilateral approaches allowed sufficient and safe decompression of the neural structures and adequate preservation of vertebral stability, resulted in a highly significant reduction of symptoms and disability, and improved health-related quality of life.

The effects of magnesium particles in posterolateral spinal fusion: an experimental in vivo study in a sheep model.

OBJECT: Magnesium has recently become a material of interest as a biocompatible and biodegradable implant metal. Authors of several reports have noted the potential bone-cell activating or bone-healing effect of high Mg ion concentrations. The classic method for achieving intertransverse process fusion involves using an autologous iliac crest bone graft. Several studies have been performed to investigate enhancement of this type of autograft fusion. To the authors' knowledge, no research has been conducted in which the efficacy of pure Mg particles in posterolateral spinal fusion has been investigated. The objective of this study was to determine whether Mg particles enhance the effectiveness of intertransverse process lumbar fusion in a sheep model. METHODS: Sixteen skeletally mature female sheep were subjected to intertransverse process spinal fusions with pedicle screw fixation at L2-3 and L5-6. Each animal was given a 5-cm3 bone autograft at one fusion level, and a combined 5-cm3 bone autograft with the addition of 1 cm3 Mg at the other level. Six months after surgery, bone formation was evaluated by gross inspection and palpation, and by radiological, histological, scanning electron microscopic, and x-ray diffraction analyses. Radiological results were graded from 0 to 4 according to the status of the bridging bone, which was determined by evaluating both x-ray films and computed tomography scans. The quality of the spinal fusion was assigned a histological score of 0 to 7, in which a score of 0 represented an empty cleft and a score of 7 represented complete bridging of bone between the transverse processes. The trabecular bone formation at each fusion level and the Ca hydroxyapatite crystalline structure in core biopsy specimens were evaluated using scanning electron microscopy and x-ray diffraction analyses, respectively. The rate of rigid bone fusion, according to both palpation and radiological assessment, in the combined Mg and autologous bone treatment group was higher (81.25%) than in the autograft bone treatment group (62.5%), but this difference was not statistically significant. The quality of bone fusion, according to the histological grading system and scanning electron microscopy inspection, was higher in the bone fusion segments of the Mg and autologous graft combined group than in the group with autograft-only arthrodesis, and this difference was statistically significant. The x-ray diffraction analyses further confirmed the effect of Mg in promoting the formation of the crystalline portion of the bone (hydroxyapatite). CONCLUSIONS: Based on the results of this study, adding Mg particles to autologous corticocancellous bone in a posterolateral intertransverse process fusion enhances the quality of bone formation. However, radiological findings did not reveal a statistically significant effect of Mg on the rate of solid bone fusion formation between the two transverse processes.

Effects of anterior contralateral cervical microdiskectomy on radiological and clinical outcome.

BACKGROUND: We have conducted a prospective study to investigate the relationship between cervical spine alignment and clinical outcome in 102 patients undergoing anterior contralateral microdiskectomy without interbody graft or cage. METHODS: Preoperative and postoperative lateral cervical radiographs were obtained, and curvature of the surgically treated spinal segments and the overall curvature of the cervical spine were evaluated in all patients. Clinical outcomes were assessed using the NDI and SF-36. RESULTS: There was no significant change in the mean overall cervical curvature (C2-C7) angles postoperatively in late follow-up findings (P = .72). It represented a statistically significant mean loss of 2.73 degrees of segmental lordosis (P < .0001). The NDI scores decreased significantly in both early and late follow-up evaluations, and the SF-36 scores demonstrated significant improvement in late follow-up results in our series. Analysis of clinical outcome showed no statistical differences between patients with segmental lordosis or kyphosis. CONCLUSION: Despite the kyphosis seen at the treated levels, the overall alignment between C2 and C7 did not change significantly, indicating that the untreated segments of the cervical spine were compensating for focal kyphosis.

A perspective for the selection of surgical approaches in patients with upper thoracic and cervicothoracic junction instabilities.

OBJECTIVE: To reach the upper thoracic vertebrae, a number of extensive approaches have been proposed. The purpose of this study is to provide a clear perspective for the selection of surgical approaches in patients who undergo vertebral body resection, reconstruction, and stabilization for upper thoracic and cervicothoracic junction instabilities. METHODS: Seventeen patients with upper thoracic or cervicothoracic junction (C7-T6) instability underwent surgery between January 1999 and May 2004. All patients presented with pain and/or neurological deficits. The causes of instabilities were 10 traumas and 7 pathological fractures. The approach chosen was primarily dictated by 3 factors including (1) type of injury, (2) level of lesion, and (3) time of admission. Ventral surgical approach was performed to all pathological and traumatic fractures causing anterior spinal cord compression. Level of lesion determined the selection of the type of ventral surgical approach, namely, supramanubrial, transmanubrial, or lateral transthoracic. On the other hand, combined (anterior and posterior) approach was performed to all late admitted trauma patients. RESULTS: Twelve anterior, 2 combined (anterior and posterior), and 3 posterior approaches were performed in this study. Anterior approaches included 3 transmanubrial, 5 upper lateral transthoracic, and 4 supramanubrial cervical dissection procedures for decompression, fusion, and plate-screw fixation depending on the levels of the lesion. The mean follow-up period was 18 months, ranging from 10 to 58 months. Nonunion or instrument-related complications were not observed. The postoperative neurological conditions were statistically significantly better than the preoperative ones (P = .003). CONCLUSION: Consideration of the type of injury, level of lesion, and time of admission can provide a perspective for the selection of side of surgical approach for this transitional part of the spinal column. This study also suggests that supramanubrial cervical approach achieves sufficient exposure up to T2, transmanubrial approach for T3, and lateral transthoracic approach below T3.

Modified transpedicular approach for the surgical treatment of severe thoracolumbar or lumbar burst fractures.

BACKGROUND CONTEXT: Conventional transpedicular decompression of the neural canal requires a considerable amount of lamina, facet joint and pedicle resection. The authors assumed that it would be possible to remove the retropulsed bone fragment by carving the pedicle with a high-speed drill without destroying the vertebral elements contributing to spinal stabilization. In this way, surgical treatment of unstable burst fractures can be performed less invasively. PURPOSE: The purpose of this study is to demonstrate both the possibility of neural canal decompression through a transpedicular approach without removing the posterior vertebral elements, which contribute to spinal stabilization, and the adequacy of posterior stabilization of severe vertebral deformities after burst fractures. STUDY DESIGN: Twenty-eight consecutive patients with complete or incomplete neurological deficits as a result of the thoracolumbar burst fractures were included in this study. All patients had severe spinal canal compromise (mean, 59.53%+/-14.92) and loss of vertebral body height (mean, 45.14%+/-7.19). Each patient was investigated for neural canal compromise, degree of kyphosis at fracture level and fusion after operation by computed tomography and direct roentgenograms taken preoperatively, early postoperatively and late postoperatively. The neurological condition of the patients was recorded in the early and late postoperative period according to Benzel-Larson grading systems. The outcome of the study was evaluated with regard to the adequate neural canal decompression, fusion and reoperation percents and neurological improvement. METHODS: Modified transpedicular approach includes drilling the pedicle for removal of retropulsed bone fragment under surgical microscope without damaging the anatomic continuity of posterior column. Stabilization with pedicle screw fixation and posterior fusion with otogenous bone chips were done after this decompression procedure at all 28 patients included in this study. RESULTS: Twenty-three of 28 patients showed neurological improvement. The percent of ambulatory patients was 71.4% 6 months after the operation. The major complications included pseudarthrosis in five patients (17.8%), epidural hematoma in one (3.5%) and inadequate decompression in one (3.5%). These patients were reoperated on by means of an anterior approach. Of the five pseudarthrosis cases, two were the result of infection. CONCLUSION: Although anterior vertebrectomy and fusion is generally recommended for burst fractures causing canal compromise, in these patients adequate neural canal decompression can also be achieved by a modified transpedicular approach less invasively.